JPH11178114A - Electrical system of electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a chopper to reduce size, weight and cost of a system apparatus and make an inverter input voltage variable to improve a system efficiency. SOLUTION: One side ends of the windings of an AC motor 103 are connected to the AC output side of a voltage-type inverter 101 which receives a DC voltage and outputs a variable AC voltage with a variable frequency and the other side ends of the windings of the AC motor are connected to each other together to form a neutral. A variable voltage type energy storage device 105 is connected between the neutral and one of the DC input terminals of the inverter 101 and an automotive DC power supply 106 is connected between both the ends of the energy storage device 105. Further, the inverter 101 is made to practise a chopper operation by switching operation of a zero-voltage mode of the inverter 101 and a power is delivered between the variable voltage type energy storage device 105 and the DC input side of the inverter 101 through the inverter 101.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric system for an electric vehicle in which a motor for driving a vehicle is driven by a voltage source inverter.

[0002]

2. Description of the Related Art FIG. 16 shows an electric system of a known electric vehicle using a battery as a power source. Reference numeral 1 denotes a main battery as a DC power supply, and a chemical battery is mainly used as a high-energy type battery. 2 is an AC motor for driving the vehicle, 3 is a variable voltage, variable frequency voltage source inverter for driving the motor,
4 is a speed reducer, 5 is a differential gear, and 6 is a wheel.
Reference numeral 7 denotes an auxiliary motor, which is a motor for driving auxiliary equipment such as an air conditioner, power steering, various pumps, etc., but only one is shown as a representative. Reference numeral 8 denotes an inverter that drives the auxiliary motor 7.

On the other hand, reference numeral 9 denotes a capacitor as a high-output type battery, and an electric double layer capacitor, which is a physical capacitor, is mainly used. Reference numeral 10 denotes a chopper inserted between the capacitor 9 and the main battery 1. In general, a high-power battery emits power when the vehicle is accelerating, and absorbs the braking energy of the vehicle when decelerating. Therefore, during acceleration, the voltage of the capacitor 9 decreases due to the release of power, and conversely, during braking, it absorbs power and increases. The chopper 10 is inserted in order to transfer electric power between the capacitor 9 whose voltage largely changes and the main battery 1 whose voltage is almost constant.

FIG. 17 shows an electric system of a series hybrid electric vehicle, and the same components as those of FIG. 16 are denoted by the same reference numerals. In FIG. 17, 11 is an engine, 12 is a generator, and 13 is a converter. 14
Is a battery, which is inserted to absorb the difference between the power generated by the generator 12 and the power consumption of the motor 2. In this series, electric power for vehicle running is generated by an engine 11, a generator 12, and a converter 13, and the electric power drives an electric motor 2 via an inverter 3. Although there are various series-type systems, the illustrated example shows a case where the chemical battery 14 is used as a battery for absorbing surplus power. Since the battery 14 is not of a high output type, a capacitor 9 which is a high output type battery is connected in parallel via a chopper 10 as in the case of FIG.

In general, the output of the generator is determined not by the maximum power required at the time of acceleration and deceleration but by the power required at the time of constant speed running, and this power is smaller than the maximum power. For this reason, at the time of acceleration / deceleration of a vehicle requiring high output, electric power is exchanged via the capacitor 9 and the chopper 10. The chemical battery 14 absorbs the difference between the power generated by the generator 12 and the power consumed by the electric motor 2 and auxiliary equipment (not shown). When the engine 11 is stopped and the vehicle runs only with the chemical battery 14, the chemical battery 14 needs to be a battery having a certain amount of energy.

FIG. 18 shows an electric system of a parallel hybrid electric vehicle, and the same components as those in FIGS. 16 and 17 are denoted by the same reference numerals. Reference numeral 15 denotes a parallel engine, 16 denotes a generator, 17 denotes a transmission, 18 denotes a chemical battery, 19 denotes a converter (inverter), 20 denotes an electric double layer capacitor as a high-output type battery, and 21 denotes a chopper. In the parallel type, the vehicle travels via the transmission 17 using only the power of the engine 15 and the case where the chemical battery 1
8 power, converter (inverter) 19, generator 1
There is a case where the vehicle travels via the vehicle 6 and a case where the vehicle travels using the power of both the engine 15 and the battery 18, and each system is used properly according to the application. Even in the parallel type, a high-output type battery is required for absorbing regenerative power during vehicle braking, and an electric double layer capacitor 20 is connected in parallel to the battery 18 via a chopper 21.

[0007]

As shown in the above-mentioned known examples, a power source for an electric vehicle requires a battery having both high-energy type and high-output type performance. High-energy batteries determine the mileage performance per charge, and high-power batteries determine acceleration performance and regenerative braking performance. If the braking energy can be sufficiently regenerated to the battery every time the vehicle is braked, the energy saving effect of the electric vehicle is very large. The driving operation of an electric vehicle is the same as that of a current engine vehicle, and the number of braking operations reaches tens of thousands of times. In order to further reduce the energy consumption of electric vehicles, it is essential to endure the tens of thousands of times of acceleration / deceleration operations. That is, it is desired that the battery withstands a large output charge / discharge operation of tens of thousands or more times. However, since current batteries are mainly chemical batteries, it is difficult to perform a high-output charge / discharge operation of tens of thousands or more times, and the number is limited to about several thousand times at most. For this reason, in the current electric vehicle, it is essential to replace the chemical battery every appropriate period or to use a high-output battery such as an electric double layer capacitor together.

FIG. 19 shows the operation modes (acceleration operation, constant speed operation, deceleration operation mode) of the electric vehicle.
(A) vehicle speed V, (b) inverter input P _i , (c)
Electric double layer capacitor voltage V _c and the inverter input voltage V _i, respectively show the output P _s of (d) a DC power source (chemical battery). FIG. 20 shows an example of the chopper used in FIGS. 16 to 18, and illustrates the chopper 10 in FIG. Reference numerals 10b and 10c denote switch sections, in which the transistors 10b1 and 10c1 and the diodes 10b2 and 10c2 are connected in anti-parallel, respectively. 10a is a current smoothing reactor, and 10d is a voltage smoothing capacitor.

Although an electric vehicle has almost the same purpose of use as a conventional engine vehicle, it has a long running distance per charge, good acceleration / deceleration performance, good fuel efficiency, and small and lightweight equipment. Something is required, and the price must be low. In this regard, the driving performance,
Fuel economy has been greatly improved. However, a major problem here is the high-power type battery unit, particularly the chopper unit as shown in FIG. Since the chopper section needs to be of a high-output type and have substantially the same capacity as the inverter for driving a motor, reduction in size and weight and reduction in price have become major issues.

Accordingly, the present invention provides an electric system for an electric vehicle in which the configuration of a chopper section among high-power type battery sections is particularly improved so that system equipment can be reduced in size and weight, cost can be reduced, and system efficiency can be improved. What you want to do.

[0011]

The operation mode of the polyphase inverter includes a zero voltage vector output. This output mode corresponds to the P-side switch arm 3 of the inverter 3 shown in FIG.
1a, 31b, 31c or N-side switch arm 32
a, 32b, and 32c are simultaneously turned on. That is, this is a mode in which all terminal voltages (line-to-line) of the polyphase motor become zero at the same time. Utilizing the zero voltage vector mode switching operation of the inverter, a DC power supply is further connected between the neutral point of the polyphase AC motor and one end of the inverter on the DC input side, and the zero voltage vector mode switching operation of the inverter is performed. A method of exchanging zero-phase power between a DC power supply and a DC input side of an inverter during a period has already been proposed.

FIG. 22 is a diagram showing this basic system, wherein 1a is a first DC power supply, 2a is a three-phase motor, 3a is a voltage source inverter, and 31a is an input capacitor of the inverter. One end of the winding 2a1 of each phase of the motor 2a is connected to the inverter 3a, and the other end is connected to all the windings collectively to form a neutral point 2a2. The second DC power supply 1b is connected between the neutral point 2a2 and one end (N pole side in the figure) of the inverter 3a on the DC input side. In such a configuration, when the zero voltage vector is output by the inverter 3a, the voltage of the DC power supply 1b becomes a zero-phase voltage when viewed from each input terminal of the electric motor 2a. The positive-phase equivalent circuit of this circuit is a drive circuit for the motor 2a using the same three-phase inverter as the conventional one. However, considering the zero-phase equivalent circuit, the three arms of the inverter 3a perform switching operation as if they were at the ratio of the zero voltage vector. Therefore, the operation of the two-quadrant chopper can be realized by controlling the zero-phase voltage by the inverter 3a. That is, according to the circuit of FIG. 22, the operation of the DC power supply 1b
DC power is transferred between the capacitor and the capacitor 31a. The reactor for the chopper uses the reactor of the winding 2a1. According to this system, since the DC input voltage of the inverter 3a can be made variable, it is possible to improve the performance of the inverter drive system, reduce the size and weight of the system, and reduce the price.

The present invention is based on the above principle,
One end of the motor winding is connected together to form the neutral point of the motor winding, and a voltage variable energy storage element such as an electric double layer capacitor or an electrochemical capacitor is connected between the neutral point and the DC input terminal of the inverter. Connect. In addition, the vehicle-mounted DC power supply is connected to both ends of the variable voltage energy storage element or both ends of the input capacitor of the inverter. By operating the inverter in the zero-voltage vector mode and using the motor winding as a reactor, the semiconductor switch of the inverter is used as a chopper switch, and an equivalent chopper is configured between the input capacitor and the inverter. Is what you do. This eliminates the need for the chopper section required in the conventional high-power battery section, and achieves a small, lightweight, and low-cost system. The motive power of an electric vehicle is generated by driving an electric motor from an in-vehicle DC power supply such as a chemical battery, an engine generator, or a fuel cell via an inverter, and the electric power of the auxiliary electric motor is generated by a variable voltage energy storage element or an inverter. Supplied from the input capacitor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining an embodiment of the invention described in claim 1. In the figure, reference numeral 101 denotes a three-phase voltage source inverter, which corresponds to the inverter 3 in FIG. Reference numeral 102 denotes an input capacitor of the inverter, and reference numeral 103 denotes an AC motor for driving a three-phase vehicle. 104 is the electric motor 1
03, and one end of each phase winding is connected to the inverter 101.
And the other end is collectively connected to form the neutral point 103a. 105 is a voltage variable energy storage element,
One end is connected to the neutral point 103a of the motor winding, and the other end is connected to the N pole side of the inverter input terminal. 1
Reference numeral 06 denotes a vehicle-mounted DC power supply, which is connected to both ends of the variable voltage energy storage element 105. In the example of FIG. 1, one end of the variable voltage energy storage element 105 is connected to the N-pole side of the inverter input terminal, but may be connected to the P-pole side.

The on-vehicle DC power supply 106 has
As described in No. 8, a chemical battery, a fuel cell, an engine generator (a DC power source constituted by an engine, a generator, and a rectifier) and the like are used. In particular, it is desirable that the on-board DC power supply 106 be a variable voltage source. Further, an electric double capacitor or an electrochemical capacitor is used for the variable voltage energy storage element.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 2 equivalently shows one phase (a phase), and the same applies to other phases. 2, the same components as those in FIG. 1 are indicated by the same numbers. Note that the inverter 101 is shown as a transistor inverter.
In FIG. 2, reference numeral 104a1 denotes an a-phase winding of the electric motor 103;
104a2 is shows the counter electromotive force of the winding 104a equivalently, is shown the size in V _m. Reference numeral 101a denotes an a-phase switch arm of the inverter 101. 101
a1, 101a2 are transistors, 101a3, 101
a4 is a diode, and these diodes 101a
3, 101a4 are transistors 101a1, 101a2
Are connected in anti-parallel. Voltage of the voltage-variable energy storage element 105 is shown in V _c, the polarity is as shown. The input voltage of the inverter 101 is shown in V _i, its polarity is as shown.

The operation when driving the electric motor 103 is as follows.
This will be described with reference to FIG. _{V c <V m, V i} > when turning on the transistor 101a2 in a state of V _c, the dashed line direction reactor current (current in the winding 104a1) I _l in FIG flows, this current gradually increases. When turning off the transistor 101a2, it charges the capacitor 102 reactor current I _l through the diode 101a3 as shown by a chain line, gradually decreases. That is, the energy stored in the voltage variable energy storage element 105 is transferred to the capacitor 102 of the inverter input circuit. The energy transferred to the input capacitor 102 is transmitted to the motor 1 by the normal inverter operation of the inverter 101.
03 is driven. In FIG. 2, the transistors 101a1,
101a2, the reactor (winding 104a1) operates as a step-up chopper.

When the electric power supplied from the on-vehicle DC power supply 106 is smaller than the required electric power of the inverter 101 when the electric motor is driven (corresponding to acceleration in an electric vehicle), the electric power is supplied from the voltage variable energy storage element 105 by the above-described operation. Is discharged and injected into the inverter 101. That is, chopper control is performed so that the inverter input voltage becomes a specified value, and power is transferred from the voltage variable energy storage element 105 to the DC input side of the inverter 101. By such control, a large amount of electric power required at the time of acceleration can be supplied from the voltage variable energy storage element 105 to the inverter 101. Should be supplied.

Next, the operation when the motor 103 is decelerating will be described with reference to FIG. FIG. 3 corresponds to FIG. 2, and the same components as those in FIG. 2 are indicated by the same numbers. V
_i> When turning on the transistor 101a1 in the form of (V _c + V _m), the reactor current I _l as indicated by the broken line in FIG flow and increases. When turning off the transistor 101a1, the reactor current I _l flows through the diode 101a4 as shown by a chain line in FIG. Since V _c <V _m , the reactor current I _l gradually decreases. FIG.
Then, the transistors 101a1 and 101a2 and the reactor (winding 104a1) operate as a step-down chopper.
That is, the power of the input capacitor 102 is transferred to the voltage variable energy storage element 105, and charges the voltage variable energy storage element 105. At the time of braking of the electric vehicle, the braking power is stored in the input capacitor 102,
This regenerative power is transferred to the voltage variable energy storage element 105 by the above-described step-down chopper operation. As in the case of acceleration, when control is performed so that most of the regenerative power is charged in the voltage variable energy storage element 105, the regenerative power to the on-vehicle DC power supply 106 can be reduced.
That is, by charging most of the regenerative power of the electric vehicle to the variable voltage energy storage element 105, the regenerative power to the on-vehicle DC power supply 106 can be made almost zero or very small. This operation corresponds to the embodiment of the invention described in claim 15.

The above-described step-up chopper operation and step-down chopper operation of the inverter 101 can be performed by causing the inverter 101 to perform an operation in a zero-voltage vector mode. , The switch arm of each phase of the inverter 101 can be equivalently regarded as a single switch arm as shown in FIGS. The step-up / step-down operation of the chopper including the switch arm and the reactor transfers power between the voltage variable energy storage element 105 and the input capacitor 102 during driving and braking of the electric motor 103. For the power supply 106, the duty of charging and discharging is greatly reduced.

FIG. 4 shows, similarly to FIG. 19, the operations shown in FIGS. 2 and 3 corresponding to the operation modes of the electric vehicle (acceleration operation, constant speed operation, deceleration operation mode). b) the input of the inverter P _i, (c) the voltage of the voltage-variable energy storage element 105 V _c and the inverter input voltage V _i, represents the output P _s of (d) vehicle DC power source 106. This figure is a view for explaining an embodiment according to claim 12. FIG. 4 shows that it is very similar to FIG. That is, by performing the chopper operation of the inverter 101 in the configuration of FIG. 1, the same function as in FIG. 19 can be provided. In FIG. 4, the voltage of the variable voltage energy storage element 105 is variable.
As shown in FIG. 2, operation is possible even at a constant level. FIG.
In the above example, the inverter input voltage is fixed. However, the inverter input voltage may be variable.

Next, FIG. 5 shows an embodiment of the invention described in claims 2 and 9, and the same components as those in FIG. 1 are denoted by the same reference numerals. The difference from the first embodiment is that the input capacitor 102 of the inverter 101 is
a, 102b, and the intermediate point (the intermediate point of the inverter DC input voltage) is connected to the voltage variable energy storage element 10.
5 is connected at one end. FIG. 6 shows the operation of the chopper according to this embodiment in correspondence with FIGS. In this embodiment, since one end of the variable voltage energy storage element 105 is connected to the intermediate point between the input capacitors 102a and 102b divided into two, V _i is replaced with V _i / 2 in the description of FIGS. Then, the operation in FIG. 6 is the same as the operation in FIGS. Therefore, a detailed description is omitted.

FIG. 7 is a diagram showing an embodiment of the invention described in claim 3. The same components as those in FIGS. 1 and 5 are denoted by the same reference numerals. In FIG. 7, a semiconductor switch arm 107 includes two transistors 107b and 107c connected in series, and diodes 107d and 107e connected in anti-parallel to these transistors. And
An intermediate point 107a between the transistors 107b and 107c and one end of the voltage variable energy storage element 105 are connected.

The operation of FIG. 7 will be described with reference to FIG.
FIG. 8 also shows one phase (a phase) as in FIG. V _m <V _c, when turning on the transistor 107b under the condition of _{V c <(V i + V} m), the reactor current I _l flows in dashed direction in the figure, the reactor current I _l is gradually increased. When turning off the transistor 107 b, the reactor current I _l is commutated to the root of one-dot chain line in FIG. V _c <(V _i
+ V _m ), the reactor current _Il decreases. In this embodiment, the switch arm 107 and the a-phase winding 104a1 of the electric motor 103 constitute a chopper.
1 is operated in the zero voltage vector mode, thereby switching the switch arm 107, thereby changing the voltage variable energy storage element 105 and the input capacitor 10
Transfer of energy between the two. The exchange of power between the voltage-variable energy storage element 105, the inverter 101, and the vehicle-mounted DC power supply 106 is also the same as in FIGS. Note that the voltage conditions under which the chopper can operate are different between FIG. 8 and FIG.

Next, FIG. 9 shows an embodiment of the invention described in claim 4. In this embodiment, the on-board DC power supply 106 connected to both ends of the variable voltage energy storage element 105 in the embodiment of FIG. 1 is connected to the DC input side of the inverter 101.
The chopper operation of No. 1 is the same as in FIGS. The average power to the inverter 101 is
Supplied from Variable voltage energy storage element 105
The transfer of electric power between the power supply and the input capacitor 102 is the same as in the embodiment of FIG. The chopper operation of the inverter 101 may be stopped in order to make the energy injection / release into the variable voltage energy storage element 105 zero. That is, the output of the zero voltage vector by the inverter 101 may be stopped. When stopping the chopper operation, it becomes the current I _c of the voltage-variable energy storage element 105 to zero, there is no transfer of energy between the input capacitor 102. When the power output from the variable voltage energy storage element 105 falls below the required input of the inverter 101, the shortage is supplied from the on-board DC power supply 106.

FIG. 10 shows an embodiment of the invention according to claim 5, in which the on-board DC power supply 106 connected to both ends of the variable voltage energy storage element 105 in FIG. Connected to.
Inverter 101 chopper operation, in-vehicle DC power supply 106
The supply of power from is the same as in the embodiment of FIG.

FIG. 11 shows an embodiment of the invention according to claim 6, wherein a vehicle-mounted DC power supply 106 connected to both ends of the variable voltage energy storage element 105 in FIG. Connected. Switch arm 107 chopper operation, vehicle-mounted DC power supply 10
The supply of electric power from 6 is the same as that of the embodiment of FIG.

FIG. 12 shows an embodiment of the invention described in claim 11, in which the same components as those in the above-described embodiments are denoted by the same reference numerals. In general, a variable voltage energy storage element is insufficient for high-frequency performance capable of coping with a switching frequency of an inverter. That is, since the high-frequency impedance is large, when used at the switching frequency of the inverter, the terminal voltage of the voltage variable energy storage element increases and the loss increases. For this reason, in the present embodiment, a capacitor for absorbing high-frequency current is connected in parallel to the voltage variable energy storage element 105. In FIG. 12, reference numeral 105a denotes a high-frequency current absorbing capacitor.

FIG. 13 shows an embodiment of the invention according to claim 19, in which a vehicle auxiliary power supply 108a for driving an auxiliary machine such as a cooler by an auxiliary motor is connected to a voltage-variable energy storage. This is a system connected to both ends of the element 105, and the configuration of the main part is shown in the example of FIG. This embodiment is described in FIGS. 5, 7, 9, 10, and 1.
1, and can also be applied to the embodiment of FIG.

FIG. 14 shows a twentieth embodiment of the present invention in which a vehicle auxiliary power supply 108b is connected to both ends of an input capacitor 102 of an inverter 101. Is shown in the example.
This embodiment is also similar to FIGS. 5, 7, 9, 10, 11,
It is applicable to the embodiment of FIG.

FIG. 15 shows an embodiment of the invention according to claim 21, which is a system in which a vehicle auxiliary power supply 108c is connected to an on-vehicle DC power supply 106, and the configuration of a main part is shown in the example of FIG. It is. This embodiment is also applicable to the embodiments of FIGS. 5, 7, 9, 10, 11, and 12.

Next, the voltage variable energy storage element 10
5 voltage V _c, the input voltage V _i of the inverter 101, the terminal voltage of the motor 103 (between lines, effective value) about the relationship V _m will be described. In the embodiment of FIG. 1, these are set as in the following equation, and the inverter 101 performs normal PWM control. The _{V i ≧ V c + V m} / √3 V i -V m / √3 ≧ V c ≧ V m / √3, in the embodiment of FIG. 5, as shown in claim 23,
These are set as in the following equation, and the inverter 101 performs normal PWM control. _{V i / 2- V m / √3} ≧ V c ≧ V m / √3- V i / 2 V i ≧ 2 (V c + V m / √3) Further, in the embodiment of FIG. 7, in claim 24 As shown,
Inverter 101 is set as a normal PWM
Perform control. V _i ≧ V _c + V _m / √30 0 ≦ V _c ≦ V _i −V _m / √3 Here, in the embodiment of FIG. good. In this case, the inverter 101 performs normal PAM control. V _i ≧ V _c + V _m / √30 0 ≦ V _c ≦ V _i / 3

[0033]

As described above, according to the present invention, a voltage variable energy storage element such as a capacitor is connected between the neutral point of the winding of the AC motor and the DC input side of the inverter, and The windings are used as reactors, and the inverters and semiconductor switch arms are operated as choppers using the zero-voltage vector mode operation of the inverters. By the above-mentioned chopper operation, during acceleration (during driving) of the electric vehicle, the energy of the voltage variable energy storage element is mainly released, and
At the time of deceleration (at the time of braking), the kinetic energy of the vehicle body is absorbed by the voltage variable energy storage element.

Therefore, there are effects such as 1) the chopper and the reactor for the chopper conventionally required can be omitted, and 2) the DC input voltage of the inverter can be made variable. is there. 3) It is possible to significantly reduce the size, weight, and cost of the system equipment. 4) Since the inverter can be operated at the optimum voltage value, the system efficiency is greatly improved. These can greatly contribute to the spread and development of electric vehicles.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the invention described in claim 1;

FIG. 2 is a diagram showing the operation of a boost chopper in FIG.

FIG. 3 is a diagram showing an operation of a step-down chopper in FIG. 1;

FIG. 4 is an operation explanatory diagram of the embodiment of FIG. 1 according to an operation mode of the electric vehicle.

FIG. 5 is a diagram showing an embodiment of the invention described in claims 2 and 9;

FIG. 6 is a diagram showing the operation of the chopper in FIG.

FIG. 7 is a diagram showing an embodiment of the invention described in claim 3;

8 is a diagram showing the operation of the chopper in FIG.

FIG. 9 is a diagram showing an embodiment of the invention described in claim 4;

FIG. 10 is a diagram showing an embodiment of the invention described in claim 5;

FIG. 11 is a diagram showing an embodiment of the invention described in claim 6;

FIG. 12 is a diagram showing an embodiment of the invention described in claim 11;

FIG. 13 is a diagram showing an embodiment of the invention described in claim 19;

FIG. 14 is a diagram showing an embodiment of the invention described in claim 20;

FIG. 15 is a diagram showing an embodiment of the invention described in claim 21;

FIG. 16 is a diagram showing an electric system of a known electric vehicle using a battery as a power source.

FIG. 17 is a diagram showing an electric system of a series-type hybrid electric vehicle.

FIG. 18 is a diagram showing an electric system of a parallel hybrid electric vehicle.

FIGS. 16 to 19 correspond to the driving modes of the electric vehicle.
It is operation | movement explanatory drawing of the system of FIG.

20 is a configuration diagram of a chopper in FIG.

FIG. 21 is a main circuit configuration diagram of a three-phase inverter.

FIG. 22 is a motor drive circuit diagram illustrating the principle of the present invention.

[Explanation of symbols]

101 Three-phase voltage source inverter 101a A-phase switch arm 101a1, 101a2, 107b, 107c Transistor 101a3, 101a4, 107d, 107e Diode 102, 102a, 102b Input capacitor 103 Vehicle driving AC motor 103a Neutral point 104, 104a1 Winding 104a2 Back electromotive force 105 Voltage variable energy storage element 105a High frequency current absorbing capacitor 106 In-vehicle DC power supply 107 Semiconductor switch arm 107a Midpoint 108a, 108b, 108c Auxiliary power supply

Claims (25)

[Claims] 1. An end of a winding of an AC motor is connected to an AC output side of a voltage type inverter that receives a DC voltage and outputs a variable AC voltage having a variable frequency, and collectively connects the other end of the winding of the AC motor. A voltage variable energy storage element is connected between the neutral point and one end of the DC input terminal of the inverter, and a voltage variable energy storage element is connected to both ends of the voltage variable energy storage element. An electric system for an electric vehicle to which an in-vehicle DC power supply is connected. 2. One end of a winding of an AC motor is connected to the AC output side of a voltage type inverter that receives a DC voltage and outputs a variable AC voltage having a variable frequency, and the other end of the winding of the AC motor is collectively connected. To form a neutral point of the motor winding, and connect a variable voltage energy storage element between the neutral point and an intermediate point of the DC input voltage of the inverter. An electric system for an electric vehicle, wherein an on-board DC power supply is connected to the electric vehicle. 3. One end of a winding of an AC motor is connected to an AC output side of a voltage type inverter that receives a DC voltage and outputs a variable AC voltage having a variable frequency, and collectively connects the other end of the winding of the AC motor. And connecting a semiconductor switch arm composed of a series circuit of two semiconductor switch elements each having a diode connected in anti-parallel to the DC input side of the inverter. An electric system for an electric vehicle, characterized in that a variable voltage energy storage element is connected between the variable voltage energy storage element and an intermediate point of the semiconductor switch arm, and a vehicle-mounted DC power supply is connected to both ends of the variable voltage energy storage element. 4. One end of a winding of an AC motor is connected to an AC output side of a voltage type inverter that receives a DC voltage and outputs a variable AC voltage having a variable frequency, and collectively connects the other ends of the windings of the AC motor. To form a neutral point of the motor winding, connect a voltage variable energy storage element between the neutral point and one end of the DC input terminal of the inverter, and connect a vehicle-mounted DC power supply to the DC input terminal. An electric system for an electric vehicle, comprising: 5. One end of a winding of an AC motor is connected to the AC output side of a voltage source inverter that receives a DC voltage and outputs a variable AC voltage having a variable frequency, and the other end of the winding of the AC motor is connected collectively. A voltage variable energy storage element is connected between this neutral point and the midpoint of the DC input voltage of the inverter, and the DC power supply is connected to the DC input terminal of the inverter. An electric system for an electric vehicle, wherein the electric system is connected to a vehicle. 6. One end of a winding of an AC motor is connected to an AC output side of a voltage type inverter that receives a DC voltage and outputs a variable AC voltage having a variable frequency, and collectively connects the other end of the winding of the AC motor. And connecting a semiconductor switch arm consisting of a series circuit of two semiconductor switch elements each having a diode connected in anti-parallel to the DC input side of the inverter, A voltage variable energy storage element is connected between a point and an intermediate point of the semiconductor switch arm, and an on-board DC power supply is connected to both ends of the semiconductor switch arm. 7. The electric system for an electric vehicle according to claim 1, wherein the inverter operates as a chopper by operating the inverter in a zero-voltage vector mode, and the voltage-variable energy is controlled. An electric system for an electric vehicle, wherein electric power is transferred between a storage element and a DC input side of an inverter via an inverter. 8. The electric system for an electric vehicle according to claim 3, wherein the semiconductor switch arm is switched and chopper-operated while operating the inverter in a zero-voltage vector mode, and the voltage-variable energy storage element is connected to the semiconductor switch arm. An electric system for an electric vehicle, wherein electric power is transferred to and from a DC input side of the inverter via the inverter. 9. The electric system for an electric vehicle according to claim 2, wherein an intermediate point of the DC input voltage of the inverter is a connection point of a plurality of input capacitors connected in series. Electrical system. 10. The electric system for an electric vehicle according to claim 1, wherein the variable voltage energy storage element is an electric double layer capacitor or an electrochemical capacitor. Electrical system. 11. An electric vehicle according to claim 1, wherein a high-frequency current absorbing capacitor is connected in parallel with the variable voltage energy storage element. Electrical system. 12. The electric system for an electric vehicle according to claim 1, wherein the voltage of the voltage-variable energy storage element or the DC input voltage of the inverter is constant, or depending on the operating state of the AC motor. An electric system for an electric vehicle, characterized by being variable. 13. The electric system for an electric vehicle according to claim 1, wherein the AC motor is a motor for driving a vehicle. 14. The electric system for an electric vehicle according to claim 1, wherein the AC motor is a motor for driving auxiliary equipment for a vehicle. 15. The electric system for an electric vehicle according to claim 13, wherein the charged energy is released from the voltage variable energy storage element during vehicle acceleration and used as drive power for the motor, and the kinetic energy of the vehicle during vehicle deceleration. The electric system of an electric vehicle is characterized in that the electric energy is absorbed and stored in a variable voltage energy storage element. 16. The electric system for an electric vehicle according to claim 1, wherein the on-board DC power supply is a chemical battery. 17. The electric system for an electric vehicle according to claim 1, wherein the on-board DC power supply is an engine generator. 18. The electric system for an electric vehicle according to any one of claims 1 to 15, wherein the on-board DC power supply is a fuel cell. 19. The electric system for an electric vehicle according to claim 1, wherein the electric power of the vehicle accessory is obtained from a variable voltage energy storage element. . 20. The electric system for an electric vehicle according to any one of claims 1 to 18, wherein the electric power of the vehicle accessory is obtained from the DC input voltage of the inverter. 21. The electric system for an electric vehicle according to any one of claims 1 to 18, wherein electric power for an auxiliary device for a vehicle is obtained from an on-board DC power supply. 22. The electric system for an electric vehicle according to claim 1, wherein the input voltage V _i of the inverter, the voltage V _{c of} the voltage-variable energy storage element, and the voltage of the AC motor. the relationship between the terminal voltage (line-to-line) V _m is the electrical system of the electric vehicle, characterized in that the following expression is satisfied. _{V i ≧ V c + V m} / √3 V i -V m / √3 ≧ V c ≧ V m / √3 23. The electric system for an electric vehicle according to claim 2, wherein the input voltage V _i of the inverter, the voltage V _{c of} the voltage-variable energy storage element, and the voltage of the AC motor. the relationship between the terminal voltage (line-to-line) V _m is the electrical system of the electric vehicle, characterized in that the following expression is satisfied. _{V i / 2- V m / √3} ≧ V c ≧ V m / √3- V i / 2 V i ≧ 2 (V c + V m / √3) 24. The electric system for an electric vehicle according to claim 3, wherein the input voltage V _i of the inverter, the voltage V _{c of} the voltage-variable energy storage element, and the voltage of the AC motor. the relationship between the terminal voltage (line-to-line) V _m is the electrical system of the electric vehicle, characterized in that the following expression is satisfied. V _i ≧ V _c + V _m / √3 0 ≦ V _c ≦ V _i −V _m / √3 25. The electric system for an electric vehicle according to claim 3, wherein the input voltage V _i of the inverter, the voltage V _{c of} the voltage-variable energy storage element, and the voltage of the AC motor. the relationship between the terminal voltage (line-to-line) V _m is the electrical system of the electric vehicle, characterized in that the following expression is satisfied. V _i ≧ V _c + V _m / √30 0 ≦ V _c ≦ V _i / 3